The present invention is concerned with the recovery of heat from hot granular solids, such as sand. In chemical processing, numerous processes exist wherein a granular material, such as sand, is heated during the processing and, with the present day energy requirements, efforts need to be made to recover heat from such solids prior to their discharge from a system.
For example, in the processing of bitumen containing oil sands, such as by solvent extraction, large quantities of hot sand are discharged from the extraction system. Recovery of heat from such solids is important in providing an economical and energy-efficient system. Such heat may, for example, be used to heat the process streams or solvents used in the extraction of the oil from the sand, or in other steps of the process.
An example of a system wherein the present process is especially useful is the process for extraction of bitumen from oil-bearing sand described in copending application Ser. No. 41,769 filed May 23, 1979 in the name of George B. Karnofsky, one of the present inventors, entitled "Method of and Apparatus for the Continuous Solvent Extraction of Bitumen from Oil-Bearing Sand," and assigned to the assignee of the present invention, the contents of said application being incorporated by reference herein. In the process described in said copending application, the hot, wet bitumen free sand, prior to discarding, is processed to recover the heat therefrom, the recovered heat used to heat the sand slurry that is to be subjected to extraction and oil separation to the desired process temperature.
Other uses of the present heat recovery process would, of course, be known to those skilled in the art relating to processing of hot granular materials that can be formed into a pumpable slurry.